CAREER: Bicrystallography-informed Mechanics of Two-dimensional Heterointerfaces

该学院早期职业发展奖将支持探索如何利用应变来研究异质界面的结构响应的研究，以设计和合成原子薄的二维材料系统。由不同的二维材料堆叠而成的异质结显示出特殊的机械和电学性质，如超润滑性、高应变耐受性和相关的电子物理。这些性质来源于二维材料形成的异质界面上的范德华相互作用。决定异质界面结构响应的一个基本特征是形成它的原子晶格之间的不可公度或不相容程度。然而，量化不可通约性及其对结构响应的影响的问题仍然是一个基本的悬而未决的问题，将在本项目中进行探索。这项研究的成功将带来一个理论和计算框架，使二维材料系统在下一代纳米溶剂和电子和光电设备等应用中得到应用。在教育和外展方面，该项目将开展艺术和科学相辅相成的跨学科STEAM活动。这些活动将直接与本科生和高中生合作，并与高中教师合作，开发以重叠的二维原子晶格背后的科学和艺术为中心的学习模块。双结晶学对二维材料体系的设计、合成和转移的主导影响，以及在宏观尺度上使用应变来控制局部微观结构的能力推动了这个项目的目标：实现应变工程作为一种途径的全部潜力，以调节异质界面中的原子重构，以获得功能性能收益。目的是根据界面的微观结构，完整地描述异质界面对温度、剪切力和法向力的响应。这项研究将开发一个统一的框架，其中双晶学是中心阶段，以探索如何在界面位错行为中表现出对不可公度的结构响应。我们将使用像Smith范式这样的代数工具来研究双结晶学，以揭示异质界面的平移对称性，并表征它们的界面位错。应变和衬底工程将通过连续和细观尺度上的界面位错和衬底晶格台阶的模拟来实现。这一结果将导致对范德华相互作用如何产生结构特性的新理解，并为系统设计和大规模合成异质结构铺平道路。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development (CAREER) award will support research to explore how strain can be used to study the structural response of heterointerfaces for the design and synthesis of atomically thin two-dimensional materials systems. Heterostructures formed by stacking distinct two-dimensional materials demonstrate exceptional mechanical and electronic properties, such as superlubricity, high strain tolerance, and correlated electronic physics. These properties originate from the van der Waals interactions at the heterointerfaces formed by the two-dimensional materials. A fundamental feature that dictates the structural response of a heterointerface is the degree of incommensurability or incompatibility between the atomic lattices that form it. However, the problem of quantifying incommensurability and its effect on the structural response remains a fundamental open question, which will be explored in this project. The success of this study will lead to a theoretical and computational framework to strain engineer two-dimensional materials systems for applications such as next generation nanolubricants and electronic and optoelectronic devices. On the education and outreach front, the project will develop transdisciplinary STEAM activities wherein Art and Science complement each other. These activities will involve working directly with undergraduate and high school students and collaborating with high school teachers to develop learning modules centered around the science and art behind overlapping two-dimensional atomic lattices. The dominant influence of bicrystallography on the design, synthesis, and transfer of two-dimensional materials systems and the ability to control the local microstructure using strain applied at the macroscale motivate this project's goal: to realize the full potential of strain engineering as a route to modulate the atomic reconstruction in heterointerfaces for functional performance gains. The objective is to completely characterize the response of heterointerfaces to temperature and shear and normal forces in terms of the interface's microstructure. This study will develop a unified framework wherein bicrystallography takes center stage to explore how a structural response to incommensurability manifests in interfacial dislocation behavior. Bicrystallography will be examined using algebraic tools like the Smith normal form to reveal the translational symmetry of the heterointerfaces and characterize their interface dislocations. Strain and substrate engineering will be realized by the modeling of interface dislocations and substrate lattice steps at the continuum and mesoscale. The outcome will lead to a new understanding of how structural properties emerge from van der Waals interactions and pave the way for a systematic design and large-scale synthesis of heterostructures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.